Re: [PATCH v2] x86/fpu: Allow PKRU to be (once again) written by ptrace.

* Kyle Huey me@kylehuey.com wrote:

diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 0531d6a06df5..dfb79e2ee81f 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -406,16 +406,7 @@ int fpu_copy_uabi_to_guest_fpstate(struct fpu_guest *gfpu, const void *buf, if (ustate->xsave.header.xfeatures & ~xcr0) return -EINVAL;

• ret = copy_uabi_from_kernel_to_xstate(kstate, ustate);
• if (ret)

• return ret;
  

• /* Retrieve PKRU if not in init state */
• if (kstate->regs.xsave.header.xfeatures & XFEATURE_MASK_PKRU) {

• xpkru = get_xsave_addr(&kstate->regs.xsave, XFEATURE_PKRU);
  

• *vpkru = xpkru->pkru;
  

• }
• return 0;

• return copy_uabi_from_kernel_to_xstate(kstate, ustate, vpkru);

} EXPORT_SYMBOL_GPL(fpu_copy_uabi_to_guest_fpstate);

So this removes 'ret' and 'xpkru' use from fpu_copy_uabi_to_guest_fpstate(), but leaves the variables in place, generating a build warning (and error with CONFIG_WERROR=y) ...

Thanks,

Ingo